tests/fixtures: Match PI const to std value

Author: joaomariolago

tests/fixtures/consts.idl

@@ -5,7 +5,7 @@ enum Status {
 };
 
 const long MAX_CLIENTS = 42;
-const double PI = 3.1415;
+const double PI = 3.141592653589793;
 const boolean FEATURE_FLAG = TRUE;
 const char NEWLINE = '\n';
 const string PRODUCT = "Blueberry";